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Energy Efficiency Optimization And Comprehensive Assessment For Wireless Sensor Network In Water Quality Monitoring

Posted on:2015-06-02Degree:DoctorType:Dissertation
Country:ChinaCandidate:J A LiFull Text:PDF
GTID:1228330428466059Subject:Systems analysis and integration
Abstract/Summary:PDF Full Text Request
Wireless sensor network (WSN) is a self-organaizing network composing of a large number of low cost, low-power tiny sensor nodes, which are spatially distributed in monitoring field. These sensor nodes can sensor, measure, and gather information from the overlay monitored area, and they work cooperatively to communicate the information through wireless links. The information detected by sensor nodes is processed and fillay sent to a sink (base staion) which either uses the information locally or is connected to other networks, for example, the Internet.With advances in sensor technology, low-power electronics, and low-power radio frequency (RF) design, WSN gets extensive applications in military reconnaissance, environmental monitoring and machine fault diagnosis. These applications need network nodes to have small size and be powered by batteries. The energy of nodes is sufficiently limited and battery charging is uneasy, so it is important to maximize the lifetime of networks and improve the energy efficiency under necessary coverage and communication connection.Energy consumption in a sensor node can be divided into’useful’or’wasteful’energy consumption. Useful energy consumption can be due to (i) transmitting/receive data,(ii) processing query requests, and (iii) forwarding queries/data to neighboring nodes. Wateful energy consumption can be due to (i) idle listening to the media,(ii) retransmitting due to packet collisions,(iii) overhearing, and (iv) generating/handing control packets. Reducing the useful or wasteful energy consumption could both save the energy of network. Mathods for saving energy could be divided into three kinds:firstly, the efficient routing technologies; secondly, the methods of data processing; thirdly, topolonogy control. There are some problems on the three methods.This paper study on the clustering protocols and propose two improved clustering protocols which balance the energy consumption and maximize the lifetime of network. Then strategies based on clustering routing protocols and algorithms based on coefficient of variation and fuzzy comprehensive index for data fusion are proposed to comprehensively evaluate water quality. At last a concept of comprehensive assessment of energy efficiency for wireless sensor network clustering protocols is proposed, and a method based on TOPSIS is proposed to comprehensively evaluate the efficiency of WSN clustering protocols. The Innovative achievements are as follows:(1) Clustering protocol design is an effective way to save energy and improve energy efficiency of WSN. In previous research, cluster heads are selected by comparing a randomly generated number with threshold, resulting that the randomness of cluster heads selection and fluctuation of number of cluster heads leads to more energy consumption. We design two protocols PNSCH and PCHSIF, whose cluster heads are selected by report package, and the selction is without randomness and comparing. The remaining energy of every member nodes is reported to cluster heads through report packages in PNSCH, and the node with most energy in cluster is selected as cluster head in next round. In PCHSIF, the information of remaining energy of member nodes and the distance between the node and base station is reported to cluster heads in current round, and the nodes with most remaining energy and nearest to base station are selected as cluster heads in next round. And the number of cluster heads of PCHSIF is optimized. The two protocols need to cosume energy to report information of remaining energy and distance to base station, but the energy dissipation is balanced and the lifetime is prolonged.(2) It is an important to reduce the overall data traffic to save energy for WSN. Because adjacent nodes in WSN have space and time correlation, there are large amounts of redundant datum. The redundant datum transmitting will waste a lot of energy.Data fusion technology could solve this problem. We propose three strategies for data fusion of WSN in water quality evaluation, and analize efficiency of three strategies. Futhermore, we propose a method to evaluate the water quality of entire monitoring area. This method introduces the coefficient of variation to determine the weight of different water quality parameters, and weakens the influence of exceptional distributed data by comprehensive weighted average method, and then fuzzy complex index is proposed to comprehensively evaluate water quality of entire nonitoring area.(3) Comprehensive assessment of energy efficiency for WSN clustering protocols is firstly proposed. Parameters about energy efficiency are studied and selected to construct a metrics system for the assessment of protocols, and TOPSIS, on of MCDM methods, is introduced into the comprehensive assessment. The same trend and normalization are added to the calculation process of TOPSIS. Then LEACH, LEACH-C, SEP and HEED are selected as examples for simulating of comprehensive assessment. And the comprehensive assessment could be divided into three parts:efficient clustering protocol selection from different clustering protocols under same cost conditions; efficient network deployment selection from different network deployment for one cluster protocol; efficient scheme selection from different clustering protocols under different cost conditions.
Keywords/Search Tags:Wireless sensor network, clustering protocol, water quality monitoring, energyefficiency optimization, comprehensive assessment, MCDM
PDF Full Text Request
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